/**
* Converts each occurrence of some consecutive number of spaces, as
* defined by $tabLength, to a tab. By default, each 4 consecutive spaces
* are converted to a tab.
*
* @param int $tabLength Number of spaces to replace with a tab
*
* @return Stringy Object whose $str has had spaces switched to tabs
*/
public function toTabs($tabLength = 4)
{
$spaces = UTF8::str_repeat(' ', $tabLength);
$str = UTF8::str_replace($spaces, "\t", $this->str);
return static::create($str, $this->encoding);
}